The temperature was 6 degrees Wednesday morning and a fresh layer of snow pitched much of Eastern Massachusetts into bunker mode, so naturally Greg Ralich decided it was no day to ride his bicycle to work.

Instead, Ralich mounted his “fat bike,” a sort of snowmobile on wheels that allows him to barrel along icy surfaces on beefy, low-pressure tires some 4 inches thick that deliver added traction for his trek from his Dorchester apartment to his job at a Somerville startup.

“It’s just more fun than driving,” Ralich said. “Who wants to sit in Boston traffic in the winter?”

Even with single-digit temperatures and icy streets, a hardy corps of local cyclists such as Ralich maintain a postal worker’s dedication to their routes: Neither snow, nor sleet, nor cold of winter deters them.

“‘Hardy’ is the kind way to put it,” said Michael Taylor, president of Forum Biopharma Advisors in Lexington, who often bikes to meetings in Cambridge — a 26-mile round trip. “Another word might be ‘crazy.’”

Hardy or crazy, there are more of them. Cycling in Boston has skyrocketed 78 percent since 2007, according to the city’s annual count of bike trips; in 2013 the city estimated there were nearly 70,000 daily bicycle trips in Boston.

‘Who wants to sit in Boston traffic in the winter?’

GREG RALICH, who’d rather be pedaling

And while many of those riders hang up their bikes during the cold months, on any given winter day cyclists are taking as many as 14,000 trips around Boston, according to estimates by Nicole Freedman, Boston’s director of bicycle programs.

Hubway, the bike-sharing service, has decided to keep its racks of rentable bicycles running during the winter in Cambridge this year and has seen a jump in those two-wheeled winter warriors.

Since the end of November, the average daily ridership in Cambridge has been 237: a fifth of normal traffic during warmer months. On a few days last week, Hubway users in Cambridge took more than 400 bike trips.

Whichever bike they ride, winter cyclists run the gamut, from typical college students, to youngsters at Kendall Square startups, to health care workers in the Longwood Medical Area. What they share is an uncommon ability to find fun in a slog that the rest of us would call miserable.

“It’s like skiing — you prepare for the cold, and it’s a blast,” Ralich said.

Public officials said they are pleased to see the uptick in green transportation.

But urban biking does present risks, especially in Boston with its narrow streets and aggressive drivers. In 2012, five cyclists were killed in accidents — though none in winter.

A subsequent report by the city of Boston determined that its Emergency Medical Services department responded to more than 1,400 cycling incidents between 2010 and 2012.

The risks increase during winter, when black ice threatens to transform every turn into an uncontrolled slide and snow banks make bike lanes narrower than usual, pushing riders closer to passing automobiles.

“I’ve come close to being doored a couple times,” Taylor said, referring to the hazard of a driver opening a door into the path of a cyclist.

What’s worse, some cyclists admit they are less likely to wear helmets during winter because they often don warm hats instead.

So why bother?

“I know this is going to sound kind of silly, but I would just love to live my life outdoors,” said Peter Parker, who spends much of his time inside a science laboratory as president of BioInnovation, an investment and consulting firm in Cambridge. “Just standing in the sunlight, even on a cold day, is so invigorating.”

Parker is among those making the Hubway winter pilot a success. He often rents a pair of wheels to cruise from meeting to meeting in Cambridge and Boston.

If the roads are too icy, then he’ll fall back to his four-wheel option. But in the main, Parker contends biking in winter is more comfortable than in a summer heat wave.

“When it’s 90, you’ll arrive a sweaty mess and then you’re not really ready for a meeting,” Parker said.

Not surprisingly Boston’s technology community seems particularly enamored of riding during winter, if only because it gives biking aficionados a whole new set of toys to try.

Taylor, for example, had a custom bike built for him by Seven Cycles of Watertown: a titanium frame, studded tires, and carbon-fiber gear belt that resists corrosion from road salt.

Working mostly out of his house for now, Taylor isn’t riding his fancy bike as much. But he recalls the routine of gearing up before his previous commute 13 miles each way along the Minuteman Trail to Cambridge: layering up from head to toe in thermal, waterproof apparel.

Often, he would have to shower and change into new clothes before starting work.

“It’s a problem to be solved: How do I stay upright and warm and get to work?” Taylor said. “And I think that appeals to people in tech. There’s kind of an engineering challenge to it.”

For others, biking through a New England winter is a point of pride, or a way to ward off holiday weight gain. “You don’t have to pay for a gym membership when you bike 14 miles a day,” quipped Shane Jordan, who runs the website BostonBiker.org.

Whatever the reason, the most committed bike commuters scoff when friends see a frigid forecast — such as the one for Friday when the wind-chill is supposed to make it feel like 9 below in the morning — and question whether they’ll keep cycling.